摘要目的:探讨基于CT图像测量HU值分析L 4退行性腰椎滑脱患者椎体间骨密度分布特点及临床意义。 方法:病例对照研究。回顾性纳入2021年1月—2022年1月河北医科大学第三医院脊柱骨科确诊的L 4退行性腰椎滑脱患者200例为观察组，其中女142例、男58例，年龄41~70（58.5±8.1）岁。纳入同期130例健康体检者为对照组，其中女92例、男38例，年龄21~70（57.6±9.3）岁。依据Schreiber法基于CT测量腰椎各椎体松质骨HU值，分析2组患者L 1~5椎体间骨密度的分布规律及差异；采用年龄、腰椎前凸顶点、滑脱程度进一步分层分析L 1~5椎体松质骨HU值的变化或差异。 结果:2组研究对象年龄、性别、身高、体质量、体质量指数等基线资料比较，差异均无统计学意义（ P值均>0.05 ）。观察组L 1~5各椎体松质骨HU值、各年龄段（41~50岁、51~60岁、61~70岁）内各椎体HU值、以L 3和L 4椎体为腰椎前凸顶点的各椎体间HU值比较，差异均有统计学意义（ P值均<0.05）；各椎体间、各年龄段内椎体间、不同腰椎前凸顶点者的椎体骨密度分布梯度均表现为L 1~3松质骨HU值逐渐下降，L 3~5松质骨HU值逐渐上升。对照组各椎体间HU值、不同腰椎前凸顶点者椎体松质骨HU值比较，差异均无统计学意义（ P值均>0.05）；各椎体间骨密度分布梯度表现为自L 1~4松质骨HU值逐渐下降，L 4~5松质骨HU值上升。观察组中，Ⅰ度滑脱患者L 1、L 2、L 3椎体松质骨HU值与Ⅱ度滑脱患者比较，差异均无统计学意义（ P值均 >0.05 ）。Ⅰ度滑脱患者L 4、L 5椎体松质骨HU值为125.16±36.99、140.39±48.57，低于Ⅱ度滑脱患者155.37±44.78、180.13±59.72，差异均有统计学意义（ t=3.12、3.10， P值均<0.05 ）。 结论:退行性腰椎滑脱患者椎体间松质骨的骨密度梯度变化折点位置相对较高，腰椎滑脱所引起的局部力学环境改变对于骨密度梯度变化的影响强于整体平衡因素，不同滑脱程度椎体松质骨HU值差异可能是滑脱进展的继发改变。

abstractsObjective:This study aimed to analyze the distribution characteristics and clinical significance of cancellous bone density in patients with L 4 degenerative lumbar spondylolisthesis based on Hounsfiled unit (HU) values by CT images. Methods:A case-control study was conducted on the imaging data of 200 patients who were diagnosed with degenerative lumbar spondylolisthesis in the Department of Spine Orthopedics in the Third Hospital of Hebei Medical University (observation group) and 130 healthy individuals (control group) who visited our hospital from January 2021 to January 2022. In the observation group, there were 142 females and 58 males, aged 41-70(58.5±8.1)years. The control group included 92 females and 38 males, aged 21 to 70 years (57.6±9.3) years.The HU value of cancellous bone in each vertebral body of the lumbar spine was measured using Schreiber method. The distribution pattern of bone density between the two groups was analyzed, and the correlation between sub-groups based on age, lumbar lordosis apex, degree of spondylolisthesis, and gradient change in HU value in vertebral cancellous bone were determined.Results:There were no significant differences in average age ,height, weight, and BMI were found (all P values >0.05). There were statistically significant differences in the HU values among all vertebral bodies in the observation group, HU values among all vertebral bodies in all age groups(41-50 years old,51-60 years old,61-70 years old), and HU values among all vertebral bodies with L 3 and L 4 as the apex of lumbar lordosis (all P values <0.05). The distribution gradient of vertebral BMD among different vertebral bodies, among different age groups and among different lumbar lordotic vertex groups showed that HU values of L 1-3 cancellous bones gradually decreased, and HU values of L 3-5 cancellous bones gradually increased. There was no significant difference in the HU value between different vertebrae in the control group and the HU value between different vertebrae in the lumbar lordotic apex group (all P values >0.05). The BMD distribution gradient between different vertebral bodies showed a gradual decrease in HU values from L 1-4 cancellous bones and an increase in HU values from L 4-5 cancellous bones. In the observation group, the HU value of cancellous bone in L 1, L 2, and L 3 vertebrae of patients with degree Ⅰ spondylolisthesis was not significantly different from patients with degree Ⅱ spondylolisthesis (all P values >0.05). The HU values of L 4 and L 5 vertebral cancellous bone in patients with degree Ⅰ spondylolisthesis were 125.16±36.99 and 140.39±48.57, respectively, which were lower than those in patients with degree Ⅱ spondylolisthesis (155.37±44.78 and 180.13±59.72), and the difference was statistically significant ( t=3.12, 3.10, all P values <0.05). Conclusion:In patients with degenerative spondylolisthesis, the position of the fulcrum point of the gradient change in cancellous bone density is relatively upward. Changes in the local mechanical environment reflected by lumbar spondylolisthesis have a stronger effect on gradient change in bone density than the overall balance factors reflected by the spinal sagittal gravity line. The difference in HU values of cancellous bone in different degrees of spondylolisthesis could be a secondary change in the progression of spondylolisthesis.